There's no shortage of iPhone cases with built-in backup batteries, but the JuiceTank is the first to instead incorporate a wall charger. So you can leave your charging cable at home, but still top off the battery wherever you find an outlet.

Desgned by Lloyd Gladstone and Jesse Pliner, the case incorporates all of the necessary charging electronics, including the plug. But it manages to stay thin thanks to the prong's clever split-folding design—an innovation that will probably be borrowed by other manufacturers for their own wall warts.

The JuiceTank's creators are currently trying to raise $125,000 through Kickstarter to put it into production, and if you are one of the first 400 people to back them you can reserve one for just $40. But if you decide to wait until they're available for sale, you can expect to shell out at least $70 instead. [Kickstarter via Ubergizmo]